/**
 * junixsocket
 *
 * Copyright (c) 2009 NewsClub, Christian Kohlschütter
 *
 * The author licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.newsclub.net.unix;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;

/**
 * The server part of an AF_UNIX domain socket.
 * 
 * @author Christian Kohlschütter
 */
public class AFUNIXServerSocket extends ServerSocket {
    private final AFUNIXSocketImpl implementation;
    private AFUNIXSocketAddress boundEndpoint = null;

    private final Thread shutdownThread = new Thread() {
        public void run() {
            try {
                if (boundEndpoint != null) {
                    NativeUnixSocket.unlink(boundEndpoint.getSocketFile());
                }
            } catch (IOException e) {
            }
        }
    };

    protected AFUNIXServerSocket() throws IOException {
        super();
        this.implementation = new AFUNIXSocketImpl();
        NativeUnixSocket.initServerImpl(this, implementation);

        Runtime.getRuntime().addShutdownHook(shutdownThread);
        NativeUnixSocket.setCreatedServer(this);
    }

    /**
     * Returns a new, unbound AF_UNIX {@link ServerSocket}.
     * 
     * @return The new, unbound {@link AFUNIXServerSocket}.
     * @throws IOException
     */
    public static AFUNIXServerSocket newInstance() throws IOException {
        AFUNIXServerSocket instance = new AFUNIXServerSocket();
        return instance;
    }

    /**
     * Returns a new AF_UNIX {@link ServerSocket} that is bound to the given
     * {@link AFUNIXSocketAddress}.
     * 
     * @return The new, unbound {@link AFUNIXServerSocket}.
     * @throws IOException
     */
    public static AFUNIXServerSocket bindOn(final AFUNIXSocketAddress addr)
            throws IOException {
        AFUNIXServerSocket socket = newInstance();
        socket.bind(addr);
        return socket;
    }

    /** {@inheritDoc} */
    public void bind(SocketAddress endpoint, int backlog) throws IOException {
        if (isClosed())
            throw new SocketException("Socket is closed");
        if (isBound())
            throw new SocketException("Already bound");
        if (!(endpoint instanceof AFUNIXSocketAddress)) {
            throw new IOException("Can only bind to endpoints of type "
                    + AFUNIXSocketAddress.class.getName());
        }
        implementation.bind(backlog, endpoint);
        boundEndpoint = (AFUNIXSocketAddress) endpoint;
    }

    /** {@inheritDoc} */
    public boolean isBound() {
        return boundEndpoint != null;
    }

    /** {@inheritDoc} */
    public Socket accept() throws IOException {
        if (isClosed())
            throw new SocketException("Socket is closed");
        AFUNIXSocket as = AFUNIXSocket.newInstance();
        implementation.accept(as.impl);
        as.addr = boundEndpoint;
        NativeUnixSocket.setConnected(as);
        return as;
    }

    public String toString() {
        if (!isBound())
            return "AFUNIXServerSocket[unbound]";
        return "AFUNIXServerSocket[" + boundEndpoint.getSocketFile() + "]";
    }

    public void close() throws IOException {
        if (isClosed()) {
            return;
        }

        super.close();
        implementation.close();
        if (boundEndpoint != null) {
            NativeUnixSocket.unlink(boundEndpoint.getSocketFile());
        }
        try {
            Runtime.getRuntime().removeShutdownHook(shutdownThread);
        } catch (IllegalStateException e) {
        }
    }

    public static boolean isSupported() {
        return NativeUnixSocket.isSupported();
    }
}
